/sci/ - Science & Math

>>4367324

Six fold symmetry is the natural result when water arranges itself into the 'most efficient' packed shape when it lines up its hydrogen bonds with other water molecules. Basically it forms miniature hexagons on the atomic level. As the crystal grows, it retains six primary axis for new molecules to bond with. Assuming new water molecules do not favor any particular face, the crystal spreads out evenly along those same six axis. Presto, hexagon.

The hexagon is a motif that frequently emerges from off-set close packing. Arrange six balls of equal size around a seventh ball of the same size to leave as little space between each object and you'll see this in action.

Water tends to form flat hexagons because its electron arrangement favors planar bonding and therefor crystal growth tends to occur in similarly planar lines.

Then there's the dendritic structure of the snowflake edges... that's something else again.

Other crystal structures are the result of different close packing methods, which are in turn, a result of their bonding symmetry.